Toward Low-Temperature Solid-Source Synthesis of Monolayer MoS2

TL;DR

This paper presents a low-temperature solid-source CVD method to synthesize monolayer MoS2 films at 560°C within a thermal budget compatible with silicon technology, achieving high-quality electronic properties.

Contribution

The study introduces a novel low-temperature solid-source CVD process for monolayer MoS2, enabling integration with silicon technology at reduced thermal budgets.

Findings

Monolayer MoS2 synthesized at 560°C in 50 min.

Achieved record high on-state current for low-temperature grown MoS2.

Mobility comparable to higher-temperature films.

Abstract

Two-dimensional (2D) semiconductors have been proposed for heterogeneous integration with existing silicon technology; however, their chemical vapor deposition (CVD) growth temperatures are often too high. Here, we demonstrate direct CVD solid-source precursor synthesis of continuous monolayer (1L) MoS$_2$ films at 560 C in 50 min, within the 450-to-600 C, 2 h thermal budget window required for back-end-of-the-line compatibility with modern silicon technology. Transistor measurements reveal on-state current up to ~140 $\mathrm{{\mu}A/{\mu}m}$ at 1 V drain-to-source voltage for 100 nm channel lengths, the highest reported to date for 1L MoS$_2$ grown below 600 C using solid-source precursors. The effective mobility from transfer length method test structures is $\mathrm{29 \pm 5\ cm^2V^{-1}s^{-1}}$ at $\mathrm{6.1 \times 10^{12}\ cm^{-2}}$ electron density, which is comparable to mobilities reported from films grown at higher temperatures. The results of this work provide a path toward the realization of high-quality, thermal-budget-compatible 2D semiconductors for heterogeneous integration with silicon manufacturing.